Characterization of hot deformation behavior of a new Ni-Cr-Co based P/M superalloy

摘要

The hot deformation behavior of a new Ni-Cr-Co based P/M superalloy was studied in the temperature range of 950-1150 °C and strain rate range of 0.0003-1 s~(-1) using hot compression tests. It was characterized by true stress-true strain curves, constitutive equation, strain rate sensitivity m contour maps, power dissipation η maps and hot processing maps. The microstructural validation of processing maps was also done. The results show that the flow stress decreases with increasing temperature and decreasing strain rate. The hot deformation apparent activation energy of the Ni-Cr-Co based P/M superalloy at peak stress is 805 kj/mol. The m and η contour maps are similar, and the values of m and η in the peak zones increase with increasing strain. When the strain is 0.5, a domain with its peak η of 40% and peak m of 25% occurs at 1050 °C and 0.0003 s~(-1), which corresponds to dynamic recrystallization and can be as an optimum condition for good workability.